电厂燃煤过程中汞控制技术研究

燃煤电厂汞控制技术分燃烧前、燃烧中和燃烧后脱汞,燃烧后脱汞技术为主要汞控制排放工艺,其中吸附剂吸附方法的研究较为广泛。基于国内外近几年燃煤电厂烟气脱汞技术的研究,综述了汞控制技术的最新进展。     

柴油低温临界吸收法回收装车挥发油气

研究了采用柴油低温临界吸收法回收装车挥发油气的效果。实验结果表明：按装车挥发油气中的总烃体积分数为20.88%、装车挥发油气流量为280 m³/h、年运行时间为2 668 h计,装置年回收油气量为291 t,装置年最大运行功率为206.770 MW,装置投资回收期为3 a;处理后净化气中的总烃体积分数为1.24%,排放质量浓度低于25 g/m³,油气回收率达95%。处理后净化气满足GB 20950—2007《储油库大气污染物排放标准》,取得了较好的环保效益和经济效益。     

抗铬菌株的筛选鉴定及其生物学特性和吸附特性

利用微生物分离纯化技术,在培养基中加入不同浓度的Cr3+、Cr6+,经过长时间驯化,从污染土壤中筛选出2株对Cr具有较高抗性的菌株(A和B),对其进行了形态、生理生化特性及分子生物学鉴定,并研究了其最佳生长条件及对Cr3+的生物吸附规律。结果表明,菌株A和B分别为蜡状芽孢杆菌(Bacillus cereus)和米根霉菌(Rhizopus oryzae)。菌株A和B的最适生长pH值均为7,最适生长温度均为30℃,最佳装液量为80~100 mL(250 mL摇瓶)。在培养时间一定时,随着Cr3+浓度的增加,菌株对Cr3+的吸附率减少,而生物吸附量则逐渐增大;在Cr3+浓度一定时,随着培养时间的延长,菌体对Cr3+的吸附率呈现出先增加后减少的趋势,这与生物吸附量的变化趋势基本一致。在Cr3+浓度为100 mg/L时,菌株A和B对Cr3+的吸附率达到最大,分别为51.47%和46.36%。     

膜吸收法净化低浓度甲醛和氨气简

基于膜吸收技术自制双层平板式膜吸收器,搭建净化低浓度甲醛和氨气污染模拟系统,考察不同膜结构参数、进气流量、吸收剂流量等因素对其净化效果的影响。结果表明,聚偏氟乙烯PVDF对低浓度甲醛和氨气的净化效率高于聚四氟乙烯PTFE。对同一材质膜,随着膜孔隙率的增大,甲醛和氨气的净化率呈上升趋势。随着进气流量的增加,甲醛和氨气的净化效率降低;而吸收剂流量对其净化效率影响不大。对于所有实验条件,平均膜孔径为0.22 μm的PVDF 4^#在进气流量u_g=120 L/h时,甲醛和氨气的净化效率最高,分别达94.7%和96.3%。     

Responses of a soil bacterium, Pseudomonas chlororaphis O6 to commercial metal oxide nanoparticles compared with responses to metal ions

The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells’ periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes.     

Photophysical and photochemical properties of the pharmaceutical compound salbutamol in aqueous solutions

Salbutamol is a potent β₂-adrenergic receptor agonist widely used in the treatment of bronchial asthma and chronic obstructive pulmonary disease. An increasing number of studies have detected salbutamol in natural water systems worldwide. Studies have shown that sunlight degrades salbutamol resulting in the formation of products; some showing higher toxicity to bacteria Vibrio fischeri than the parent compound. In this contribution, steady-state absorption and emission techniques, high-performance liquid chromatography, and transient absorption spectroscopy are used to investigate the photochemistry of salbutamol in aqueous buffer solutions at controlled pH values. Ground- and excited-state calculations that include solvent effects are performed to guide the interpretation of the experimental results. Salbutamol is sensitive to UVB light absorption in the pH range from 3 to 12, forming products that absorb light at longer wavelengths than the parent compound. Quantum yields of degradation reveal that the deprotonated species is 10-fold more photo-active than the protonated species. In line with this result, the fluorescence quantum yield of the protonated species is more than an order of magnitude higher than that of the deprotonated species. Transient absorption spectroscopy shows that population of the triplet state occurs with a rate constant of 7.1 × 10⁸ s⁻¹ in the protonated species, while a rate constant of 1.7 × 10¹⁰ s⁻¹ is measured for the deprotonated species. While degradation of the deprotonated species is not affected by the presence of molecular oxygen, a twofold increase in the photodegradation yield of the protonated species in air-saturated conditions is observed.     

O3氧化结合化学吸收同时脱硫脱硝的动力学及热力学研究

构建了O3氧化多种污染物的反应机制,并对O3氧化SOx、NOx过程进行动力学模拟,然后利用热力学原理计算出Ca(OH)2和CaCO3湿法烟气同时脱硫脱硝吸收反应达到平衡时SOx和NOx的分压力.结果表明,Ca(OH)2作吸收剂湿法烟气同时脱硫脱硝比CaCO3作吸收剂效果好,而且两者几乎100％地去除烟气中的SOx和NO...     

火电厂CO2捕集与封存技术探讨

火电厂CO2减排技术主要包括燃烧前处理、燃烧中减排及燃烧后捕集三类。介绍了IGCC、富氧燃烧、胺吸收法、生物法等CO2捕集与封存技术,分析其存在问题及应用前景。     

Nanocatalyzed biodiesel synthesis from the oily contents of Marine brown alga Dictyota dichotoma

This research article demonstrates biodiesel synthesis through the methanolysis of the oily contents (4.02 ± 0.27% w/w on dried basis) of Dictyota dichotoma collected from the coast of Hawksbay, Pakistan. The metal oxides (CaO, MgO, ZnO, and TiO₂) used as nanocatalysts were refluxed (5% K₂SO₄), calcinated (850 °C) and characterized by Atomic Force Microscopy (AFM) which produced 93.2% w/w FAME (biodiesel) at relatively mild condition (5% catalyst, 65 °C, 3 h, 18:1 molar ratio) using CaO. Whereas, MgO, ZnO, and TiO₂ produced 92.4%, 72.5%, and 31.8% w/w FAME, respectively at elevated condition (225 °C). Thus, CaO was considered to be the best catalyst among the others. This tri-phase reaction require continuous fast mixing and the yield depends on the reaction parameters like catalyst amount, temperature, reaction time and molar ratio (methanol: oil). The reusability of these heterogeneous catalysts simplified the purification step, reduced the waste generation and make the final product technically and economically viable.     

尾气循环技术在国内顺酐装置的应用

顺酐生产过程排放的废气中含有大量未反应原料、副产物CO和挥发性有机物(VOC)等,对其进行处理使之达标排放,回收其中可利用的物质或能量有重要意义。吐哈石化厂顺酐装置采用CONSER公司工艺技术,新增部分尾气回收生产工艺路线,回收40%的尾气中的正丁烷,实现了蒸汽分阶利用,排放的废气中SO2、NOx、颗粒物等达到GB16297-1996《大气污染物综合排放标准》中二级标准。